Wydział Chemii

Klaudia Szczerba

Andrzej Mular

Karolina Piasta

Karolina Kamińska

Òscar Palacios

Merce Capdevila

Elżbieta Wojaczyńska

Elżbieta Gumienna-Kontecka

2026

Inorganic Chemistry

65

21382-21395

10.1021/acs.inorgchem.6c03994

Naukowa

Angielski

Artykuł

The 2-(2-hydroxyphenyl)- and 2-(2,3-dihydroxyphenyl)thiazoline motifs appear repeatedly across microbial siderophores, yet the thermodynamic properties of their Fe(III) complexes remain fragmentarily described. Herein we present the Fe(III) coordination chemistry of anguibactin (Ang), the siderophore of Vibrio anguillarum, together with four designed analogs (L1–L4) that pair a phenol- or catechol-thiazoline core with an auxiliary donor group, either carboxylate or hydroxamate, analyzing the contribution of each functional group against a common scaffold. Using physicochemical analyses in MeOH/H₂O (80:20, w/w), we determined the protonation equilibria, complex stoichiometries, pH-dependent speciation, and Fe(III) affinities. At physiological pH all ligands form bis-ligand complexes in which iron is bound through the phenolate–thiazoline unit and the auxiliary donor rather than a catecholate sphere. Replacing the carboxylate by a hydroxamate unit substantially increases Fe(III) affinity. Of importance, Ang retains the highest affinity of the series (pFe = 28.2), exceeding that of closely related desferrithiocin and being close to other efficient siderophores, like tris(hydroxamate) ferrioxamines or pyoverdine, a peptide-based siderophore comprising dihydroxyquinoline, hydroxamate, and catecholate motifs. As Ang has been proposed as a thermally stable counterpart to acinetobactin – a siderophore from the multidrug-resistant pathogen Acinetobacter baumannii, the structure–property relationships can support the future design of arylthiazoline-based “Trojan horse” siderophore–antibiotic conjugates.

Aromatic compounds, Deprotonation, Hydrocarbons, Ligands, Equilibrium constant

CC-BY

http://dx.doi.org/10.1021/acs.inorgchem.6c03994

https://www.acs.org/content/acs/en.html